Even amateurs can take aurora photos

Posted: Sunday, November 03, 2002

Perhaps you've seen photos of the aurora, or tried to take one of an aurora, constellations or a meteor shower by yourself.

With just three pieces of equipment -- a Single-Lens-Reflex camera with a B-bulb setting, a cable release (costs about $15 at a camera store) and a tripod -- just about anybody can take such photos. Here's some tips.

First, any type of light pollution messes up the exposure. Take time-exposures outside of town, the darker the area, the better, for example, the turn-outs on Bridge Access Road seem ideal.

This is how to set up the equipment once camera, cable release and tripod are attached to each other: use a normal 50mm lens, perhaps even a 28mm because they give a larger field-of-view and allow longer exposures without star trails; set the exposure on "B." The film I prefer is ASA 400, but any speed will work. Open the aperture (smallest number) because stars are faint. They're very far, so use infinity.

The longer an exposure, the brighter stars become and more fainter ones appear. As a rule of thumb, divide 1,000 by focal length, for example 1,000/50 equals 20 seconds. You can, or perhaps should, take longer exposures for meteor showers and aurorae, but notice star trails will show up (stars seem to move because we're rotating).

Start the exposure by pressing the cable's button, tighten the screw, count the seconds, then stop the exposure by loosening the screw. Next picture.

(Log on to my home page at http://chinook.kpc.alaska.edu/~ifafv/ and access my astrophotography lecture for more details. I also will offer a noncredit class on the topic in January.)

This month's Leonid meteor shower will peak around 1:30 AST, the night of Nov. 18-19. Its radiant is in the constellation of Leo on the southeast horizon. As Earth orbits our sun through space, we're crossing the orbit of comet Temple-Tuttle (as we're heading toward Leo), which leaves debris in the form of dust and grains behind, and those are the particles that burn up in our atmosphere, creating meteors that seem to streak away from Leo, therefore they emerge from the southeast.

It's easy to find Leo, since the Lion seems to swallow bright Jupiter. The Leonids have been in the press during the past few years as they're good only every 33 years and this is the last good year.

(Log on to skypub.com, astronomy.com or check out the newest issues of these monthly magazines: Sky and Telescope and Astronomy, at your local library. The Kenai Community Library carries them.)

This month, Saturn is the first bright planet to emerge in the evening. Find it using the accompanying diagram of the constellation Taurus on the east horizon, part of which looks like an arrow head or the snout of a bull, while two more stars to the left make up the horns of the bull. If you have a telescope, you should be able to see the rings. (If you don't have one, I'd be happy to answer questions if you'd like to buy one.)

Using binoculars, check out the star clusters of the Pleiades and the Hyades (the arrow head next to the Red Giant star Aldebaran).

Andy Veh is the physics and astronomy instructor at Kenai Peninsula College. This column will appear on the first Sunday of each month. He can be reached at aveh@uaa.alaska.edu.

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